1. Field of the Invention
The present invention relates to an IC-card manufacturing apparatus suitable for manufacture of thin, non-contact-type IC cards.
2. Description of the Related Art
IC cards containing electronic components such as IC chips are generally known. Such an IC card must be manufactured such that the card has no uneven surface which would otherwise result due to accommodation of an electronic component therein. Therefore, methods and apparatuses for manufacturing such an IC card have been proposed in Japanese Patent Publication No. 2(1990)-16234 and in Japanese Patent Application Laid-Open Nos. 6(1994)-176214, 9(1997)-277766, and 11(1999)-48660.
Meanwhile, a thin, flexible, non-contact-type IC card having a thickness of a few hundreds of micrometers has recently been put in practical use. FIG. 17 shows a typical IC-card manufacturing apparatus 100 for manufacturing such a thin, non-contact-type IC card. The IC-card manufacturing apparatus 100 includes a lower press platen 101 and an upper press platen 102. The lower press platen 101 is attached to a base 104 via a heat-insulating plate 103, and the upper press platen 102 is attached to an elevation member 106 via a heat-insulating plate 105. Thus, the lower press platen 101 serves as a stationary platen, and the upper press platen 102 serves as a movable platen. Heaters 107 and coolant passages 108 are provided within the lower press platen 101, and heaters 109 and coolant passages 110 are provided within the upper press platen 102. Further, a tubular lower chamber member 111 is provided on the base 104 in order to cover the circumference of the lower press platen 101, and an upper chamber member 112 is provided on the elevation member 106 in order to cover the circumference of the upper press platen 102. When the upper press platen 102 is lowered, the lower chamber member 111 and the upper chamber member 112 mate to thereby form a sealed chamber 113. Reference numeral 114 denotes an evacuation port provided on the upper chamber member 112. An unillustrated evacuator (e.g., a vacuum pump) is connected to the evacuation port 114 in order to enable evacuation of air from the chamber 113. Reference numeral 115 denotes a seal member provided on the upper chamber 112.
In such an IC-card manufacturing apparatus 100, a laminated substrate M used for fabrication of an IC card is placed on the lower press platen 101. The laminated substrate M is configured as shown in FIG. 16. Reference character P denotes an electronic component which is composed of an IC chip Pi and an antenna Pa and is mounted on a base sheet S. The base sheet S and the electronic component P are sandwiched by hot-melt sheets Ta and Tb, which are in turn sandwiched by thermoplastic resin sheets (sheets of, for example, polyethylene terephthalate) La and Lb, which carry adhesive layers Ba and Bb, respectively. Subsequently, the laminated substrate M is subjected to thermocompression bonding. Specifically, after the elevation member 106 shown in FIG. 17 is lowered, air is evacuated from the chamber 113, and the laminated substrate M is pressed by means of the lower press platen 101 and the upper press platen 102, which have been heated through supply of electricity to the heaters 107 and 109. Thus, the laminated substrate M undergoes thermocompression bonding in a state in which air bubbles have been removed from the interior of the laminated substrate M. Subsequently, the supply of electricity to the heaters 107 and 109 is stopped, and cooling water is supplied to the coolant passages 108 and 110, whereby the laminated substrate M is cooled.
Incidentally, when a thin, flexible IC card is manufactured, the states of heating and pressure-application during thermocompression bonding of the laminated substrate M greatly affect production quality. For example, when heating control is not performed properly, a manufactured product loses its flatness due to generation of warpage or distortion, and when pressure control is not performed properly, problems such as layer shifting and partial delamination occur easily, resulting in deterioration and variation in quality and decreased commercial value.
In view of the forgoing, the above-described conventional IC-card manufacturing apparatus 100 is designed such that each of the lower press platen 101 and the upper press platen 102 performs the heating step and the cooling step to thereby, secure continuity in heating control and pressure control. However, since a longer production cycle time is needed to complete fabrication of the laminated substrate M, productivity and mass-production efficiency are low, and increased energy consumption makes energy conservation and economy difficult to achieve.
The above-described problems can be solved through employment of a system in which the heating step and the cooling step are performed at different stages (locations). However, in this case, when the laminated substrate M is transferred from the stage for the heating step to the stage for the cooling step, heating and pressure application are cancelled, resulting in deterioration and variation in quality and decreased commercial value.
In view of the foregoing, the assignee of the present invention has proposed an IC-card manufacturing apparatus (basic apparatus) which comprises a laminated-substrate sandwiching unit including upper and lower sandwiching members for sandwiching a laminated substrate M in a sealed state; an evacuation unit for evacuating air from the interior of the laminated-substrate sandwiching unit; a pre-heating press unit for elevating the temperature of the evacuated laminated-substrate sandwiching unitxe2x80x94which holds the laminated substrate Mxe2x80x94to a pre-heating temperature lower than a regular heating temperature; a thermocompression-bonding press unit for receiving the laminated-substrate sandwiching unit transferred from the pre-heating press unit and for heating the laminated-substrate sandwiching unit to the regular heating temperature to thereby effect thermocompression bonding; and a cooling press unit for receiving the laminated-substrate sandwiching unit transferred from the thermocompression-bonding press unit and for cooling the laminated-substrate sandwiching unit (Japanese Patent Application Laid-Open No. 2000-182014).
Since this basic apparatus is equipped with a laminated-substrate sandwiching unit, the laminated substrate M can be accommodated within the evacuated laminated-substrate sandwiching unit in a sealed state, so that the heated state and the pressurized state can be maintained continuously; i.e., the temperature and pressure of the laminated substrate M can be maintained. As a result, commercial value can be increased greatly by means of improved quality,and homogeneity.
Incidentally, the laminated-substrate sandwiching unit provided in the above-described basic apparatus has upper and lower sandwiching members each consisting of a frame portion and a plate portion. The plate portion projects outward from the pressure-application surface of the press platen, and its circumferential edge portion is fixed to the frame portion. Therefore, the frame portion and a peripheral portion of the plate portion located outside the press platen are not heated, even if the interior portion of the plate portion in direct contact with the press platen is heated to high temperature, so that the plate portion assumes a shape of a wok (a convex shape) due to the difference in thermal expansion between the central and peripheral portions of the plate portion.
In this case, when the plate portion is thin, the deformation of the plate portion is suppressed by means of pressure applied from the press platen. However, when the thickness of the plate portion is 1 mm or greater, the plate portion deforms even in a state of pressure being applied from the press platen. Although the amount of deformation is relatively small, the deformation makes it impossible to press the laminated substrate M into a precise thickness or to effect pressing itself, when the laminated substrate M has a thickness of a few hundreds of micrometers. Further, when pressure applied to the plate portion is removed, the laminated substrate M (IC card) separates from the plate portion, causing: a variation in cooling speed with resultant variation in glossiness and/or generation of wrinkles. As described above, when the thickness of the plate portion increases, the basic apparatus causes various problems such as deterioration and variation in quality, decrease in commercial value, and decrease in yield (productivity).
Moreover, in order to increase the productivity of the basic apparatus, each press unit must be opened and closed at high speed. However, since the basic apparatus is equipped with a laminated-substrate sandwiching unit including upper and lower sandwiching members for sandwiching a laminated substrate M in a sealed state, opening a press unit at high speed causes a phenomenon such that the plates of the upper and lower sandwiching membersxe2x80x94which are in close contact with the opposite pressure-application surfaces of the press unitxe2x80x94are attracted by the opposite pressure-application surfaces, so that the upper and lower sandwiching members may be deformed and pull apart from each other. Although the deformation is small, the influence of the deformation on fabrication becomes impossible to ignore when the laminated substrate M (IC card) has a thickness of a few hundred micrometers, with the result that fabrication failure such as failure in thermocompression bonding occurs. Accordingly, the quality of IC cards deteriorates and varies, and the commercial value and yield of the IC cards decrease. In addition, the limit in relation to high speed open/close operation of each press unit lowers productivity and mass-production efficiency.
Furthermore, in such a basic apparatus, at the beginning of a pressure application step, the laminated substrate M is pressed by means of the upper and lower press platens in a state in which the thermoplastic sheets La and Lb of the laminated substrate M have not yet been plasticized sufficiently. Therefore, a relatively large pressure acts on the IC chip Pi itself, resulting in possible breakage of the IC chip Pi. Further, since the laminated substrate M has a sheet-like shape and a thickness of a few hundreds of micrometers, slight displacement of the press platen causes a great variation:in the applied pressure, with the result that pressure cannot be applied to the laminated substrate M in an accurate and stable manner. In order to solve this problem, an improved manufacturing apparatus has been proposed (see, for example, Japanese Patent Publication Nos. 1(1989)-54173 and 4(1992)-26299). In the improved apparatus, at least one of press platens is supported by an air cushion unit. Thus, the pressure applied to the press platen by means of a drive mechanism can be varied from a considerably low pressure to an intermediate pressure (or high pressure) in an accurate and stable manner. Such a conventional manufacturing apparatus has a single air cushion unit, which is suitable for applying a uniform pressure across the entire surface of a substrate to be pressed, but is not suitable for fabrication of thin IC cards, which must be of highly uniform thickness.
An object of the present invention is to provide an IC-card manufacturing apparatus which can bond a laminated substrate through thermocompression bonding by use of paired plate portions which always have a high degree of parallelism, to thereby increase production yield (productivity).
Another object of the present invention is to provide an IC-card manufacturing apparatus which can improve the quality and homogeneity of IC cards, remarkably increase yield and commercial value of the IC cards, and improve productivity and mass-production efficiency through realization of high speed open/close operation of a press unit.
Still another object of the present invention is to provide an IC-card manufacturing apparatus which can apply to a laminated substrate an accurate and stable pressure ranging from a considerably low pressure to an intermediate pressure (or high pressure), without being affected by the thickness of the laminated substrate, thereby enabling production of high-quality IC cards of uniform thickness.
In order to achieve the above objects, the present invention provides an IC-card manufacturing apparatus for manufacturing an IC card from a laminated substrate consisting of an electronic component, such as an IC chip, and sheet members, including thermoplastic-resin sheets, which sandwich the electronic component. The IC-card manufacturing apparatus is equipped with a thermocompression-bonding press unit which applies heat and pressure to the laminated substrate from opposite sides thereof by use of paired press platens having pressure-application surfaces to thereby effect thermocompression bonding. According to one aspect of the present invention, the IC-card manufacturing apparatus comprises a laminated-substrate sandwiching unit which is independent of the main body of the IC-card manufacturing apparatus and includes upper and lower sandwiching members for sandwiching the laminated substrate in a sealed state. Each of the upper and lower sandwiching members has a plate portion equal in size and shape with the corresponding pressure-application surface or projecting outward from the pressure-application surface by a predetermined amount; a frame portion bigger than the plate portion; and a connection portion which connects the plate portion and the frame portion and absorbs thermal deformation of the plate portion. During a process for applying pressure and heat to the laminated substrate, each press platen is brought into pressure contact with the corresponding plate portion so as to apply pressure and heat to the plate portion. In this process, each plate portion may deform (expand) due to heat (high temperature). However, by virtue of this configuration, such deformation is absorbed by the connection portion (a plurality of connection strips), so that the laminated substrate is bonded through thermocompression bonding by the paired plate portions which have high degree of parallelism at all times.
According to another aspect of the present invention, the IC-card manufacturing apparatus comprises at least one air passage which is formed in each press platen and has at least one air jetting opening formed on the pressure-application surface of the press platen; an air supply unit for supplying air to the air passage; and a control unit for controlling the air supply unit so as to supply air to the air passage for a preset period of time when the paired press platens are opened. By virtue of this configuration, when the paired press platens are opened, for a preset period of time air is supplied to each air passage from the air supply unit controlled by the control unit. Thus, air is jetted from the air jetting opening provided on each pressure-application surface. As a result, the laminated-substrate sandwiching unit is quickly separated from the pressure-application surfaces simultaneously with the opening of the press platens.
According to still another aspect of the present invention, at least one of the press platens is composed of a press-platen main body having a pressure-application surface and a press-platen base for applying pressure to the press-platen main body. A plurality of air cushion units are disposed between the press-platen main body and the press-platen base to be located at different positions; and a pressure setting unit for independently setting the respective pressures of the air cushion units is provided. By virtue of this configuration, when the thickness of the laminated substrate varies with position, the pressures of the respective air cushion units at different positions are set individually by the pressure setting unit; specifically, the pressure in a region corresponding to a thick portion of the laminated substrate is increased, whereas the pressure in a region corresponding to a thin portion of the laminated substrate is decreased. Through this pressure setting, the paired pressure-application surfaces for pressing the laminated substrate can be made parallel.